The brightest minds in our field have been trying to find a definition of science fiction for these past seventy years. The short answer is, science fiction stories are given as possible, not necessarily here and now, but somewhere, sometime.
The perversity of the Universe tends towards a maximum.
Anything you don't understand is dangerous until you do understand it.
The witnessing of titanic events is always dangerous, usually painful, and often fatal.
If one must explain a magic trick, one should do so after the show is over.
The Unexpected always comes at the most awkward times.